北海五龙亭和瘦西湖五亭桥虽身处异地，建造年代不同，但二者都运用了（）的构图法则。

A、应时而借

B、多样统一

C、空间远近对比

D、尺度与比例

You are underway and pass by a lighthouse. Its light，which was white since you first sighted it，changes to red. This means（）.

A.the light is characterized as alternately flashing

B.the lighthouse has lost power and has switched to emergency lighting

C.it is the identifying light characteristic of the lighthouse

D.you have entered an area of shoal water or other hazard